Prepartion of liquid detergent compositions



United States Patent 3,075,922 PREPARATION OF LIQUID DETERGENT COMPUSITIONS Harold Eugene Wixon, Jersey City, N.J., assignor to Colgate-Palmolive Company, New York, N.Y., a corporation of Delaware No Drawing. Filed Aug. 1, 1957, Ser. No. 675,562 6 Claims. (Cl. 252138) The present invention relates to the preparation of a heavy-duty detergent liquid composition comprising a mixture of a water-soluble carboxyalkylcellulose salt and a water-soluble polyphosphate salt, as hereinafter described and claimed.

The present application is a continuation-inpart of abandoned applications Serial No. 532,734 and 532,735, filed September 6, 1955, and Serial No. 581,299, filed April 30, 1956.

In the detergent art, it is known to prepare detergent compositions in powdered form, such as obtained by the spray-drying of a slurry of a detergent composition. These powdered products may comprise an organic detergent, and inorganic salts such as sodium tripolyphosphate, pyrophosphate, sulfate and silicate, etc. Various organic materials including sodium carboxymethylcellulose have been incorporated also.

The preparation of a detergent composition in the form t of a stable, homogeneous liquid suspension comprising polyphosphate salts and carboxyalkylcellulose salt involves particular consideration of variances in manufacturing procedure in conjunction with the nature of the ingredients so as to obtain optimum results. For example, the admixture of sodium carboxymethylcellulose powder with substantial amounts of polyphosphate salts to form a concentrated aqueous system may result in a marked tendency for instability of the product. This incompatibility may be evidenced by the formation of two or more immiscible phases such as by the precipitation or separation of the carboxymethylcellulose from solution or by a tendency for the settling of the phosphate salts as a hard cake in the bottom of the container.

In accordance with the present invention, it has been found that a heavy-duty liquid detergent composition may be prepared in the form of a pourable, substantially homogeneous and stable suspension by a method of preparation embodying a particular sequence of operations dependent upon the character of the ingredients and form of the composition as herein described. More particularly, the present invention relates to the preparation of a stable, homogeneous, pourable, liquid suspension comprising forming a solution of said water-soluble carboxyalkylcellulose salt in water, admixing therewith watersoluble inorganic polyphosphate salt with agitation to form a homogeneous solution comprising said carboxyalkylcellulose salt, polyphosphate salt and water, and mixing the same with a water-soluble organic detergent with agitation to form a homogeneous suspension.

Such product exhibits many desirable characteristics including, particularly, maximum stability of the suspension without the formation of immiscible liquid phases or of a precipitate over long periods of time. The liquid detergent composition retains its attractive appearance as a pourable, substantially homogeneous opaque suspension upon aging. The composition may be prepared in such stable form without the necessity for hydrotropic compounds or special suspending agents by use of the instant manufacturing procedure and selected ingredients.

This suspension is of relatively high solids content and may be utilized conveniently by the consumer by the addition of small portions of the liquid to a laundering bath or the like. In general, the composition exhibits a washing power during laundering that is comparable to the 3,075,922 Patented Jan. 29, 1953 commercial heavy-duty detergents in powder form, par-' ticularly with respect to soil redeposition power.

In the formulation of such product, the ingredients should be selected and proportioned in accordance with the described method so as to form a suspension having the foregoing qualities. As indicated the suspension is pourable and is free-flowing upon light shaking of the container at room temperature. The viscosity of the suspension may be varied accordingly but the product should have an apparent viscosity from about 50 to about 7,000 centipoises, and preferably about 500 to about 6,000 centipoises for optimum results. The above references to viscosity and any others set forth in this application are determined by a Brookfield viscometer, Model HAF, using a No. 1, 2 or 3 spindle (depending upon the viscosity) at '10 rpm. and at room temperature, i.e. 20 C. The suspension may be employed in any suitable container or packaging material such as metal, glass or plastic in the form of bottles, cans, drums or bags.

The proportions of the materials in the final product are variable to some degree. The amount of the carboxyalkylcellulose salt is a minor proportion such as about 0.2 to 5 parts, and preferably about 0.5 to 3 parts by weight and the polyphosphate content will be about 5 to 45 parts, and preferably about 10 to 30 parts, by weight of the composition as formulated. The organic detergent is about 5 to 30 parts, and preferably about 10 to 25 parts, by weight. The above proportions are based upon 100 parts by weight of the finished formulation. In general, the ratio of organic detergent to polyphosphate salt will be from about 0.1 to 2 parts detergent to about 1 part of polyphosphate salt.

The solids content is from about 15 to parts, and preferably about 30 to 60 parts, whereas the aqueous liquid suspending medium or solvent is about 25 to 7 parts, and preferably about 40 to 70 parts by weight of parts of the formulation. It is preferred that water is the liquid medium, particularly where the solids content is from about 15 to 60 parts of the final product. Where a higher solids content is desired such as up to 75 parts, it may be advantageous to reduce or modify the viscosity of 'a given formula by adding to the water a minor amount of a compatible organic solvent. Examiples of suitable water-miscible solvent materials are a lower aliphatic monohydric alcohol (e.g. ethanol or isopropanol) and urea which may be employed in an amount less than about 15 parts and preferably not in excess of about 5 ,parts by weight of the product.

As indicated, it is an essential element of the present invention to form a homogeneous solution by theadmixture of the polyphosphate salt with an aqueous solution of the carboxyalkylcellulose salt. The obtention of this type of composition is dependent in part upon the initial r formation and use of an aqueous solution of the carboxyalkylcellulose salt.

The water-soluble carboxyalkylcellulose salt is preferablythe alkali metal carboxy lower alkyl cellulose salts such as the sodium and potassium salts of carboxymethylcellulose. Such materials are available usually in the 'form'of a powder, having a few percent (e.g. 5%) of moisture, in various grades of purity and viscosity in s olu- ,tion. The commercial grades of sodium carboxymethylcellulosehaving a purity from about 60% and up to ,1100% on a dry basis and which are of low, medium or high viscosity may be employed if desired. It is preferred to employ such salts having a viscosity of about 20 to 1,000 centipoises in a 2%"concentration in water. The degree of substitution of the carboxymethyl group per anhydroglucose unit in the cellulose molecule is variable but is usually about 0.5 to 2, preferably up to subtitution.

The sodium carboxymethylcellulose' or the like is peratures a nt m about S to 45 parts by weight. This mixed solution" is utilized in the present invention in the form of an aqueous solution. The carboxyalkylcellulose particles should be dispersed thoroughly in the water in order to form a uniform colloidal dispersion. The preparation of this carboxyalkylcellulose salt solution in the absence of the polyphosphate permits adequate'swelling and hydration of the cellulosic material. Moreparticula rly, the cellulosic salt in particulate form should be added slowly to the water with efiicient stirring to form a homogeneous and substantially colorless solution without lumps or the like. This solution is poura-ble at room temperature and has usually a viscosity of about 50 to 6,000centipoises, preferably at least about 100 centipoises at room temperature at the time of preparation. The amount of water is variable and the indicated proportion of about 0.2'to parts of the cellulosic salt is admixed with any desired proportion of the water, usually at least 5 parts water, which is sufiicient to obtain the desired solution with the indicated processing'conditions. In general, the use of'increasing amounts of the cellulose salt will require greater amounts of water and it is most efficient'to operate with solution of less than about 15% concentration by weight, preferably from about 0.1 to concentration. a

After the preparation of the car-boxymethylcellulose solution, the polyphosphate salt is admixed with the'carboxyalkylcellulose to form a pourable, smooth, homogeneous, gel-like solution or'dispersion. In the resulting solution, the polyphosphate salt is dissolved 'or finely dispersed in the colloidaldispersion'of the carboxyalkylcellulose salt depending upon the solubilityand proportion'of the polyphosphate. It is highlystable with no observable separation over long periods of time. The polyphosphate salt may be incorporated in anysuitable form such as in the form of a dry powder or in the form of any convenient solution or dispersion in water depending upon the'specific polyphosphate salt. The temperature of the admixture is not critical and the ingredients maybe mixed at room temperature or at lower or higher temsuch as up to about 160 F. In themanufacture of the mixed solution, requisite care should be taken to insure the formation of a uniform system since the polyphosphate salt has a tendency to" salt-out the carboxyrnethyloellulose salt from solution. The polyphosphate salt should be added slowly with etlicient sti'rring'o'r mixing action to'prevent separationor'theformation, of an undesirable precipitate. Such mixing operation will vary in degree dependent upon the size' of thebatch, type of stirrer, etc., but is a readily ob'servableand determinable state.

This homogeneous solution of the'carboxyalkylcellulose salt and polyphosphate salt may contain a variable amount of water proportioned so as to achieve the desired state. In general, the water conteiitfwill' be ii-om about 5 to 85' parts by weight and preferably '10 to 70 parts, since either a desired proportion' or "the total amount of water which is present in the final product may be incorporated at this stage of 'the' process. It is preferred to add a portion of the water later when the organic detergent is added toiorinthesusp'ension. 'As indicated, the carboxyalkylcellul'ose will 'be present in' an 0.2 to 5 parts and the polyphosphate' from usuallyturbid and of variable viscosity. It has a'visco'sity usually from about 50 to 6,000 centipoi'ses, preferably from about 100' to 4,000 centipoises, dependingupori the amount of water present and the. proportions of the other ingredients.

HAS indicative of the significance of defscribed' sequence of steps for obtention of this solution, it has been found that, if the carboxyalkylcellulose salt in the form of a dry powder is added with agitation toa suspension or solution of the polyphosphate salt in water, there does .uetresult the desired state but rather the product tends to form two phases with the carboxyalkylcellulose 'suspended as discrete'particles. It is'clear that the-formation of stable gel-like solutions is dependent in large measure upon the type of ingredients and the order or particular sequence for admixture. F

The water-soluble polyphosphate sa'lts may be considered as'derived from orthophosphoric acid or the like by theremoval of water though they may be formed byany suitable means of manufacture. These watersoluble molecularly dehydrated or condensed phosphate salts are known in the art and comprise the alkali metal, ammonium, alkylamine --and alkylolamine salts of tripolyphosphoric, pyrophosphoric and tetraphosphoric acids, and the like. "It is preierred to use a potassium polyphosphate salt in view of its generally greater solubility in wateras compared to the corresponding sodium salt. More particularly, potassium pyrophosphate or a combination in any suitable proportions of potassium pyrophosphate and sodium tripolyphosphate hexahydrate s s ro 2 be utilized in'the'manufacture of detergent compositions or m-ay be employeddirectly for-washing and cleansing purposes. More particularly, it may be admixed with suitable organic detergents and additional water, if desired, to form a stable, heavy-duty liquid detersive suspension. The organic-detergent is preferably a sulfonated detergent which is-selected from the group consisting of the water-soluble anionic organic sulfate and 'sulfonate detergents; though water-soluble non-ionic-or- 'ganic detergents may be incorporated also. These materials are-known and have sufiicientwater solubility or dispersibility to form foaming and detersive aqueous solutions in the concentrations which aresuitable for use, e.g.

inwashing dishes, laundry and the like. They may be 'usedindividually or in any desired combination.

-A suitable synthetic detergent is a water-soluble higher alkyl aryl sulfonate detergent, particularly those having about '8 to 15 carbon-atoms in the alkyl group.

It is preferred to use-the higher alkyl benzene sulfonate detergent for optimum effects, though other similar detergents havinga mononuclear 'aryl-nucleus, such astoluene, xylene, or phenol, may be used also. The higher alkyl-substituenton the aromatic nucleus maybe branched or straightchained-in structure; examples of such group beingnonyl, decyl, keryl, and tetradecyl and pentadecyl groups derived from polymers of lower mono-olefins, and the like.

Examples-ofsuitable aliphatic detergents are the normal and secondary higher alkyl sulfate detergents, particularly those having about'S to 15 carbons in the fatty alcohol residue, such 'as lauryl (or coconut fatty alcohol) sulfate. Other suitabledetergents'are the sulfuric-acid 'esters of polyhydric alcohols incompletely esterified with higher fatty acids,*e.g. coconut oil monoglyceride mono sulfateythe higher fatty acid-esters of low molecular weight alkylol sulfonicacids, e.g. oleic acid ester of isethionic acid; the higher fatty acid (e.g. coconut) ethan- 'olamide sulfate; the higher fatty acid amide of amino alkyl sulfonicacids, e.g. lauric acid-amide of :taurine; and

the like.

Thesefsulfate and sulfonate detergents are used in the form oftheirwater soluble salts; such as the alkali metal and "nitrog'en containing, e.g. lower alkylolamine, salts. Examples are'the sodium, potassium; ammonium, isopropanolamine, monoand tri-ethanolaniine "salts of said higher alkyl benzene sulfonate, higher alkyl sulfate and the like. In commercial practice, it is preferred to use the alkali metal salts.

Examples of suitable nonionic detergents are the watersoluble non-ionic polyalkylene oxide detergents. In general, these detergents are the products produced by the introduction of a controlled number of alkylene oxide groups into an organic hydrophobic compound or group, usually of an aliphatic or aromatic structure. The hydrophobic organic group contains usually at least about 8 carbons, and preferably up to 30 carbons, condensed with at least about 5 and usually up to about 50 alkylene oxide groups. It is preferred to use the polyoxyethylene condensates derived from ethylene oxide, although other lower alkylene oxides such as propylene oxide, butylene oxide and the like have generally similar properties and may be substituted therefor.

Among the non-ionic detergents, it is preferred to use the polyakylene oxide condensates of alkyl phenol, such as the polyoxyethylene ethers of alkyl phenols having an alkyl group of at least about 6, and usually about 8 to 12 carbons, and an ethylene oxide ratio (number of moles per phenol) of about 7, 9, 12 and 20, though the number of ethylene oxide groups will be usually from about 8 to 18. The alkyl substituent on the aromatic nucleus may be diisobutylene, diamyl, polymerized propylene, dimerized C C olefin, and the like. 7

Further suitable detergents are the polyoxyalkylene esters of organic acids, such as the higher fatty acids, rosin acids, tall oil acids, or acids from the oxidation of petroleum, etc. These polyglycol esters will contain usually from about 12 to about 30 moles of ethylene oxide or its equivalent and about 8 to 22 carbons in the acyl group. Suitable products are refined tall oil acids condensed with 16 or 20 ethylene oxide groups, or similar polyglycol esters, of lauric, stearic, oleic acids, etc.

Additional non-ionic agents are the polyalkylene oxide condensates with higher fatty acid amides, such as the higher fatty acid primary amides, monoand diethanolamides. Suitable agents are coconut fatty acid amide condensed with about to 50 moles of ethylene oxide. The fatty acyl group will have about 8 to 22 carbons, and usually about 10 to 18 carbon atoms, in such products. The corresponding polyalkylene oxide condensates of higher fatty acid sulfonamides maybe used also if desired.

Other suitable polyether non-ionic detergents are the polyalkylene oxide ethers of higher aliphatic alcohols. Suitable fatty alcohols having a hydrophobic character, preferably 8 to 22 carbons, are lauryl, myristyl, cetyl, stearyl and oleyl alcohols which may be condensed with an appropriate amount of ethylene oxide, such as at least about 6 and preferably about 10 to 30 moles. A typical product is oleyl alcohol condensed with about 12, or moles of ethylene oxide. The corresponding higher alkyl mercaptansor thioalcohols condensed with ethylene oxide are suitable in the present invention also. The water-soluble polyoxyethylene condensates with hydrophobic polyoxypropylene glycols may be employed also.

Further suitable non-ionic detersive-type materials which may be added are the higher fatty acid alkanolamides, such as the monoethanolamides, diethanolamides and isopropanolamides wherein the acyl radical has about 10 to 14 carbon atoms. Examples are coconut fatty acid, lauric, capric and myristic diethanolamides, and the corresponding monoethanolamides and isopropanolamides. These alkanolamide materials tend generally to improve the foaming power and detergency of the detergent compositions and may be solubilized in the liquid.

The organic detergent is admixed with the carboxyalkylcellulose-polyphosphate solution in any suitable manner to form the final liquid product. The organic detergent may be added as a dry powder but it is preferred to employ an aqueous solution of the detergent (including a suspension, gel, dispersion or slurry of the organic detergent in water, since the presence of Water is not critical but facilitates the mixing of the ingredients. The detergent solution is preferably warmed, e.g. about B, so that any additional ingredients to be added which are'of limited water-solubility, such as lauric isopropanolamide, are present in molten form. It is preferred that the organic detergent solution be a concentrated solution, such as of the order of a 20 to 75% organic detergent by weight.

The initial carboxyalkylcellulose-phosphate salt solution is then admixed slowly with the detergent with efiicient stirring at room temperature (or at elevated temperature if desired) to form a homogeneous and uniform liquid opaque suspension. The viscosity of the suspension may be varied as indicated by control of the proportions of the ingredients. The initial mixed solution may be added to the detergent solution or the reverse order may be employed as desired.

Various other ingredients may be added as desired in cluding compatible perfumes, coloring materials, corrosion or tarnish inhibitors, germicides, bleaching agents, optical bleaches or fluorescent dyes and the like. Other phosphate materials or builder salts may be included in the product provided that they do not substantially adversely affect the desired results. The physical characteristics of the product may be modified in degree by the incorporation of various compatible materials as desired to modify or adjust the viscosity or other characteristics of a given formula. Suitable examples are small amounts of waxes (e.g. castor wax) and colloidal materials such as bentonite and similar clays.

The following examples are additionally illustrative of the nature of the invention and it will be understood that the invention is not limited thereto. All parts are by weight unless otherwise specified.

Examples I-III These suspensions are prepared in the following manner: As Part A, the carboxymethylcellulose powder (66% pure) is mixed with the water slowly with stirring to form a fluid gel-like solution having a viscosity of 136 centipoises. The pyrophosphate of Part B in powder form is added to the carboxymethylcellulose solution at room temperature. This phosphate salt is added slowly in increments over a period of about 10 minutes, with stirring of the carboxymethylcellulose solution to form a homogeneous solution gel having a viscosity of about 2,500 centipoises.

The ingredients in Part C are then mixed together to form a uniform homogeneous mixture. The dodecyl benzene snlfonate detergent in powder form (84% pure) is dissolved in the Water (with color added) and heated to 150 F. The isopropanolamide in Examples I and III is melted and then slowly added to the detergent solutions with stirring to form a uniform mixture which is a mobile gel having a viscosity of about 13,000 centipoises. The Part C of Example II which does not have the amide is a solution.

The initial gel-like mixture of carboxymethylcellulose and polyphosphate are then added to the detergent mixtures of Part C with stirring at room temperature to form a uniform and homogenerous liquid suspension. The viscosity of the final product is about 1,150 centipoises for Example I, 768 centipoises for Example II and 2,016

centipoises for Example III. 'Ihese suspensions havebeen found to be extremely stable with no significant separation after many weeks of storage. They are markedly superior in stability to similar suspensions which do not contain carboxymethylcellulose or in which the carboxymethylcellulose was added in powder form to a polyphosphate solution.

Examples lV-Vl IV V VI Part A:

Sodium carboxymethylcellulose 1. 35 0. 90 1. 36 Water 14. 95 13. 56 13. 11 Part B:

Tetrapotassium pyrophosphate 19.93 4. 52 Sodium tripolyphosphate hexahydratm 22. 6O 13. 56 Water 14. 95 13. 56 20. 80 Part Sodium dodecyl benzene snltonate (dry powder 85% pure) 11.46 Sodium dodecyl benzene sulronate (48.5%

aqueous slurry) 18. 63 18. 63 Lauric-myristie isopropanolamide (l: 1) 4. 98 4. 52 4. 52 Color l. 00 0. 90 0. 90 Water 31. 38 25. 33 22.60

Viscosity, c.p 1, 408 4, 000 1,184

These suspensions are prepared by the same procedure as in Examples I to III. Part B is prepared by adding the phosphate salt slowly to the water with stirring. In Formula IV the phosphate salt is dissolved to form a solution and in Formulas V and VI the phosphate salts are dispersed to form a suspension. The Part B products are added slowly to the Part A solution with strong mixing action at room temperature as described to form the desired homogeneous gel-like solution.

The ingredients of Part C are mixed similarly to form a uniform homogeneous mixture. The initial gel-like solutions comprising the carboxymethylcellulose and phosphate are then added to the liquid gel-like mixtures of Part C with stirring at room temperature which results in the formation of a uniform and homogeneous liquid suspension. These suspensions have been found to be extremely stable also.

Although the present invention has been described and illustrated with a reference to specific examples, it is understood that modifications and variations of composition and procedure are contemplated within the scope of the appended claims.

Having thus described the invention, what is claimed is:

1. A processfor preparing a detergent composition in the form of a substantially stable. and homogeneous, pourable liquid which comprises preparing an aqueous solution of sodium carboxymethylcellulose in a concentration from about 0.1 to by weight, subsequently adding a polyphosphate selected from the group consisting of potassium pyrophosphate in particulate form and aqueous solutions thereof slowly and with agitation to said cellulose solution to form a pourable, homogeneous liquid, and thereafter admixing said oellulose-pyrophosphate solution with an alkali metal alkyl benzene 'sulfohate having 8 to carbons in the alkyl group, the proportions thereof being 0.2 to 3 parts of said cellulose salt, 10 to 30 parts of said pyrophosphate, 5 to 30 parts of said alkyl benzene sulfonate and the balance being pri- 5. marily water based upon 100 parts by weight of the formulation and suificient to form a substantially stable and homogeneous, pourable liquid.

2. A liquid detergent composition prepared by the process of claim 1.

1g 3. A process for preparing a detergent composition in the form of a substantially stable and homogeneous, pourable liquid which comprises preparing an aqueous solution of an alkali metal carboxy lower alkyl cellulose salt in a concentration from about 0.1 to 15% by weight,

15 subsequently adding a water-soluble inorganic polyphosable, homogeneous liquid, and thereafter admixing said cellulose-polyphosphate solution with a water-soluble higher alkyl benzene sulfonate detergent having about 8 to 15 carbons in the alkyl group, the proportions thereof being 0.2 to 5 parts of said cellulose salt, 5 to 45 parts of said polyphosphate, 5 to parts of said sulfonated detergent, and the balance being primarily water based upon 100 parts by weight of the formulation and sufficient to form a substantially stable and homogeneous, pourable liquid.

30 4. A process in accordance with claim 3 wherein said polyphosphate is potassium pyrophosphate and said sulfonated detergent is an alkali metal higher alkyl benzene sulfonate.

5. A process in accordance with claim 3' wherein said polyphosphate is sodium tripolyphosphate hexahydrate and said sulfonated detergent is an alkali metal higher alkyl benezene snlfonate.

6. A liquid detergent composition prepared by the process of claim 3.

OTHER REFERENCES Trexler: Phosphates, Soap and Sanitary Chemicals, July 1950, pp.,3941 and 82.

Hercules CMC, Cellulose Gum, Properties and Uses of Copyright 1951 by Hercules Powder Co., 20 pages.

.lVIonsanto TechnicalBulletin No. P 139, Sodium Tripolyphosphate, Monsanto Chem. C0,, St. Louis, July 8, 

1. A PROCESS FOR PREPARING A DETERGENT COMPOSITION IN THE FORM OF A SUBSTANTIALLY STABLE AND HOMOGENEOUS, POURABLE LIQUID WHICH COMPRISES PREPARING AN AQUEOUS SOLUTION OF SODIUM CARTBOXYMETHYLCELLULOSE IN A CONCENTRATION FROM ABOUT 0.1 TO 10% BY WEIGHTM SUBSEQUENTLY ADDING A POLYPHOSPHATE SELECTED FROM THE GROUP CONSISTING OF POTASSIUM PYROPHOSPHATE IN PARTICULATE FORM AND AQUEOUS SOLUTIONS THEREOF SLOWLY AND WITH AGITATION TO SAID CELLULOSE SOLUTION TO FORM A POURABLE, HOMOGENEOUS LIQUID, AND THEREAFTER ADMIXING SAID CELLULOSE-PYROPHOSPHATE SOLUTION WTH AN ALKALI METAL ALKYL BENZENE SULFONATE HAVING 8 TO 15 CARBONS IN THE ALKYL GROUP, THE PROPORTIONS THEREOF BEING 0.2 TO 3 PARTS OF SAID CELLULOSE SALT, 10 TO 30 PARTS OF SAID PYROPHOSPHATE, 5 TO 30 PARTS OF SAID ALKYL BENZENE SULFONATE AND THE BALANCE BEING PRIMARILY WATER BASED UPON 100 PARTS BY WEIGHT OF THE FORMUATION AND SUFFICIENT TO FORM A SUBSTANTIALLY STABLE AND NOMOGENEOUS, POURABLE LIQUID. 